ceph/src/boost/libs/mpl/include/boost/mpl/empty_base.hpp

   1
   2 #ifndef BOOST_MPL_EMPTY_BASE_HPP_INCLUDED
   3 #define BOOST_MPL_EMPTY_BASE_HPP_INCLUDED
   4
   5 // Copyright Aleksey Gurtovoy 2001-2004
   6 //
   7 // Distributed under the Boost Software License, Version 1.0.
   8 // (See accompanying file LICENSE_1_0.txt or copy at
   9 // http://www.boost.org/LICENSE_1_0.txt)
  10 //
  11 // See http://www.boost.org/libs/mpl for documentation.
  12
  13 // $Id$
  14 // $Date$
  15 // $Revision$
  16
  17 #include <boost/mpl/bool.hpp>
  18 #include <boost/mpl/aux_/config/msvc.hpp>
  19 #include <boost/mpl/aux_/config/workaround.hpp>
  20 #include <boost/mpl/aux_/lambda_support.hpp>
  21
  22 #include <boost/type_traits/integral_constant.hpp>
  23 #include <boost/type_traits/is_empty.hpp>
  24
  25 namespace boost { namespace mpl {
  26
  27 // empty base class, guaranteed to have no members; inheritance from
  28 // 'empty_base' through the 'inherit' metafunction is a no-op - see
  29 // "mpl/inherit.hpp> header for the details
  30 struct empty_base {};
  31
  32 template< typename T >
  33 struct is_empty_base
  34     : false_
  35 {
  36 #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
  37     using false_::value;
  38 #endif
  39 };
  40
  41 template<>
  42 struct is_empty_base<empty_base>
  43     : true_
  44 {
  45 #if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
  46     using true_::value;
  47 #endif
  48 };
  49
  50 }}
  51
  52 namespace boost {
  53
  54 template<> struct is_empty< mpl::empty_base >
  55     : public ::boost::integral_constant<bool,true>
  56 {
  57 public:
  58     BOOST_MPL_AUX_LAMBDA_SUPPORT_SPEC(1,is_empty,(mpl::empty_base))
  59 };
  60
  61 }
  62
  63 #endif // BOOST_MPL_EMPTY_BASE_HPP_INCLUDED